The binary format command allows you to convert a number into a character (or more generally, a binary string). The advantage of this first method is that you can easily create strings with characters that can not be found directly on the keyboard.

By selecting characters at random from a given string you can control both which characters you get in the output and their relative frequency (by duplicating characters that should appear more often).

Note that these are only two techniques, it is possible to come up with many more, some variations on the theme (by using non-uniform random distributions for instance), some different techniques altogether, for instance Markov chains. If you have an interesting method (for instance indeed Markov chains), then please add them!